From German Patent 195 45 561, a wet-type rotor pump with a pump wheel is known which takes in a feed medium through an intake channel and feeds it towards a discharge channel. The pump wheel is mounted on a shaft. A motor armature of a motor is mounted on the same shaft. The feed medium flowing around the motor armature is used to cool the motor and possibly provided electronic components. For feeding electrically conductive liquids, the motor armature is surrounded by a slit pot. The stator package of the motor with the windings is arranged outside the slit pot preferably consisting of plastics. By means of the slit pot through which a gap is formed between the motor armature and the inside of the pot, in which gap feed medium is able to flow, a sealing of the motor armature with respect to the environment is guaranteed. Wet-type rotor pumps utilized for feeding electrically non-conductive liquids such as gasoline have no slit pot since no sealing with respect to the stator package and the windings is required.
The common shaft supporting the motor armature and the pump wheel is supported by two radial bearings, one in the region of the pump wheel and one at the opposite end of the shaft in the slit pot or in a housing. Due to the pressure differences in the feed medium, axial forces occur. Additionally, the motor transfers axial forces to the shaft due to the magnetic forces. For the axial support, it is known to mount an axial bearing to the rotor, which is supported on a bearing seat inserted in the slit pot. In wet-type rotor pumps, only sliding bearings can be used both as radial and as axial bearings since the service life of ball and roller bearings within liquids is too short. The provision of an axial bearing between slit pot and rotor makes the assembly of the wet-type rotor pump more complicated.